Apparatus for production of titanium metal



1956 J. c. PRISCU ETAL 3 APPARATUS FOR PRODUCTION OF TITANIUM METAL Filed Oct. 18, 1951 2 Sheets-Sheet 1 INVENTORS John C. Priscu Junior W. Whitney Fig. I.

Oct 9, 1956 J. c. PRISCU EIAL 2,755,033

APPARATUS FOR PRODUCTION OF TITANIUM METAL Filed Oct. 18, 1951 2 Sheets-Sheet 2 Fig. 2. M

INVENTORS John C. Priscu Junior W. Whitney APPARATUS FOR PRODUCTIQN F TITANIUM METAL John C. Priscu, Atlantic Highlands, and Junior W.

Whitney, Fords, N. J., assignors to National Lead Company, New York, N. Y., a corporation of New Jersey Application October 18, 1951, Serial No. 251,903

3 Claims. (Cl. 266-17) The present invention relates in general to the production of titanium metal and, more particularly, to improved apparatus for reacting titanium tetrachloride with magnesium metal.

In the production of titanium metal by the process described in the Kroll U. S. Patent No. 2,205,854, titanium tetrachloride is reacted with a reducing metal, such as magnesium or calcium, in a retort under normal pressure to form a titanium metal sponge in the presence of the chlorides of the reacting metal. This results in the formation of a substantially solid fused mass of material which is chipped from the retort or furnace in the form of small lumps of metal. These lumps of metal are then subjected to prolonged leaching treatments to separate the titanium metal from the occluded metallic chlorides. This process is not only costly and time-consuming but the titanium metal recovered by this process is frequently of inferior quality due to the prolonged exposure of the metal to the atmosphere during the removal of the sponge from the reaction pot and the subsequent leaching operations.

Improvements over the Kroll process for producing titanium metal have been made, noteworthy of which is the process described in the copending application of Carl K. Stoddard et 211., Serial No. 164,644, filed May 27, 1950, now Patent No. 2,663,634, wherein titanium metal is produced in a highly pure state by continuously removing the reaction products from the titanium metal sponge as the latter is being formed and in the absence of an.

Although these and other processes have had considerable commercial success the apparatus of the instant invention has provided unusually high efficiencies with relatively small losses of reacting materials, high quality of product, few operational difiiculties, and low maintenance costs.

An object of the invention is to provide improved apparatus for producing substantially pure titanium metal in an economical and efficient manner.

A still further object of the invention is to provide improved reducing and distilling apparatus for forming substantially pure titanium metal wherein the reduction of titanium tetrachloride with magnesium metal and the subsequent removal of the residual reaction products from the titanium metal sponge by distillation is carried out without exposing the titanium metal to the atmosphere and without loss of the reaction products and/or the titanium metal from the reaction pot.

With the above and other objects in view it will appear to those skilled in the art from the present disclosure that this invention includes all features in the disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fatented Oct. 9, 1956 Fig. 1 is a front elevation in section of the improved reduction and distillation apparatus of this invention, showing the cover of the reaction pot in its closed position;

Fig. 2 is a top plan View of the apparatus of Fig. 1;

Fig. 3 is a transfer section of the apparatus on line 33 of Fig. 1;

Fig. 4 is a perspective view of the collar of the reaction P Fig. 5 is a perspective view of the base plate to the reaction pot; and

Fig. 6 is a perspective view of the inverted cover of the reaction pot.

Referring to the drawings, the improved apparatus of this invention comprises a casing, indicated generally at 10, which is a hollow, substantially cylindrical member, as shown on Figs. 1, 2 and 3, having a base-portion 11 at its lower end of reduced cross-section; and a head-portion 12 at its upper end of enlarged cross-section. Both the base-portion 11 and the head-portion 12 are closed by end walls 13 and 14 respectively which are detachably secured, by bolts or equivalent fastening-means 15 and 16, to the corresponding ends of the casing to seal the latter from the atmosphere. In the preferred embodiment of the invention, the casing and end walls are formed of heavy gauge mild sheet steel but it Will be understood that any other suitable material may be used. Extending substantially laterally from one wall of the enlarged head-portion 12 of the casing is an elbow shaped conduit, indicated generally at 17, the inner end of which intersects the enlarged head-portion of the casing and the outer end of which is flanged so as to be connected into a vacuum line (not shown) for evacuating the air from the casing and maintaining subatrnospheric pressure therein. in this respect the enlarged head-portion 12 of the casing constitutes the condensing zone of the apparatus as and for the purpose hereinafter described. Intermediate its closed ends the casing is provided on its inner wall with a plurality of annular reinforcing rings 18 in vertically spaced relationship for reinforcing the wall of the casing.

The reaction zone of the apparatus is identified by a reaction pot indicated generally at 1?. The latter is a container in which the reaction of the titanium tetrachloride with the magnesium metal takes place and preferably comprises a relatively heavy gauge stainless steel cylindrical shell 29 closed at its bottom by a separable base-plate and at its top by a removable cover as hereinafter described. The overall diameter of the shell of the pot is less than the inside diameter of the casing so that when the reaction pot is mounted therein there will be an annular clearance space 21 between the outer wall of the reaction pot shell and the reinforcing rings 13 of the casing as shown in Fig. l. The overall length of the reaction pot is shown as being substantially one-third the overall length of the casing such that the reaction pot is adapted to be mounted therein intermediate its lower reduced end and its upper enlarged head-portion. The upper end of the cylindrical wall of the reaction pot shell is preferably formed as a separable collar 2% the lower end of which is adapted to slip into the open upper end of the cylindrical shell of the reaction pot 19 and to be supported therein by an annular external head 24)!) arranged to seat on the upper edge of the pot. The upper end of the separable pot collar Ztla is open and provided with an annular inwardly turned flange 22 which is substantially inverted V shaped in cross-section and provides an annular outwardly and downwardly sloping cover-seat 23, and an annular inwardly and downwardly sloping flow-control lip 24. Although a separable pot collar is lid/766,033

preferred for convenience in removing the titanium metal sponge from the reaction pot, it will be understood that the pot collar may be formed as an integral part thereof.

The lower end of the cylindrical reaction pot shell is also open and is adapted to rest upon a substantially flat circular base-plate 25 which serves as an end-wall for closing the lower end of the reaction pot shell whenever the latter is mounted thereon, the base-plate 25 being, in turn, mounted on suitable supporting means indicated generally at 26. In the embodiment of the invention shown in the drawings, the supporting means 26 comprises a pair of I-beams secured in spaced, substantially parallel relationship in the lower part of the casing; and an apertured supporting-plate resting on the I-oearns and serving as a support for the aforesaid base-plate 25.

Referring to Figs. 1 and 5, the base-plate is essentially dish-shaped and comprises a disk having an annular upstanding peripheral flange 27 the upper edge of which constitutes a substantially flat annular seat which serves to support the lower end of the reaction pot shell. Although it is preferred to form the annular flange 27 as an integral part of the base-plate disk, the flange may constitute a separate ring-shaped member fastened to the base-plate disk by a welded joint or the like.

In accordance with this construction, the joint formed between the lower end of the reaction pot shell and the annular seat of the base-plate is elevated above the plane of the base-plate. This construction insures against the molten magnesium metal and magnesium chloride leaking out from beneath the lower end of the reaction pot shell during the initial stages of the reaction and accumulating between the walls of the pot and the casing. Thereafter, as the titanium metal sponge begins to form over the bottom of the base-plate and to extend up the side walls of the reaction pot, it automatically seals off the joint between the reaction pot shell and the base-plate, thereby preventing the egress of molten magnesium products therefrom during the remainder of the reaction. Thus the practical convenience of a reaction pot having a separable base-plate is retained while avoiding the severe losses of molten magnesium products and titanium metal sponge which have been experienced with earlier types of reaction pots.

Pursuant to further objects of the invention, the baseplate 25 is provided with a vertical aperture 28 which is adapted normally to be closed by valve-means, such as, for example, a tapered plug 29 adapted to be actuated externally of the apparatus by operating-means, such as, for example, a rod 30 which is attached at its lower end to the plug and extends upwardly through a fluid tight seal 39 in the casing in the manner shown. By manipulating the plug-operating rod 30 an operator may open and close the aperture 28 in the bottom of the base-plate and thus control the amount of magnesium chloride permitted to accumulate in the bottom of the reactor pot.

In order to provide further control of the reacting materials during the reaction, the upper open end of the reaction pot is adapted to be selectively closed and opened by means of a cover 31 so that during initial stages of the operation the reacting products in the reaction pot may be confined therein by closing the cover on the pot. On the other hand, during the distillation stage of the reaction, the cover is adapted to be raised to permit the reaction products to be distilled therefrom in the manner hereinafter described. To these ends, the cover 31 of the pot comprises a relatively thick disk-shaped member formed of cast iron or equivalent material and provided with a substantially central aperture 32 extending substantially vertically therethrough. The under side of the cover is adapted to be suitably shaped to control the egress of volatile chlorides from the reaction pot when the cover is lifted, and in one form of the invention the under side or bottom of the cover is provided with an inverted substantially conical-shaped center-protuberance 33, the periphery of which comprises an annular flange 34, the slope of which is opposite to that of the conical protuberance and corresponds substantially to the slope of the cover-seat 23 on the upper end of the reactive pot collar. Thus upon lowering the cover 31 onto the pot collar the annular reverse flange 34 of the cover makes a relatively close fit with the cover-seat of the reaction pot collar to prevent the escape of the volatile products of the reaction. Upon raising the cover to permit the volatile chlorides to be distilled olf, the surface of the cone-shaped center protuberance 33 of the cover, in conjunction with its reverse flange 34, will direct the volatile chlorides upwardly and outwardly away from the central aperture 32 in the cover thus inducing the volatile chlorides to flow up into the condensing portion of the casing thereby minimizing the escape of the volatile chlorides from the reaction pot by way of the central feed pipe hereinafter described.

Extending upwardly from the top surface of the cover and circumscribing the central aperture 32 thereof, is a substantially cylindrical guide-sleeve 35 which is adapted to slidingly engage the exterior walls of a cylindrical feed pipe 36 which is secured at its upper end in the end wall 14 of the casing and extends downwardly therefrom with its lower end terminating adjacent the upper end of the reaction pot. The diameter of the feed pipe 36 is slightly less than the diameter of the guide-sleeve 35 and the central aperture 32 of the cover so that the latter may slide up and down on the feed pipe. In this respect the feed pipe 36 constitutes guide-means for the cover. As shown especially well in Figs. 1 and 2, the upper end of the feed pipe 36 is provided with a lateral branch 37 which intersects the end wall 14 of the casing and which is used to feed volatile titanium tetrachloride into the reaction pot; the main portion of the feed pipe constituting feed-means for delivering solid pieces of magnesium or sodium metal into the reaction pot. The portion of the feed pipe which extends above the top end wall 14 of the casing is provided with an air lock chamber, indicated schematically at 38, whereby the magnesium metal may be introduced into the feed pipe without permitting the admission of air into the reaction pot.

In order that the cover may be selectively raised and lowered relative to the reaction pot, a pair of lifting rods 4 )40 are provided, the lower ends of which are secured in the cover at substantially diametrically opposite points thereof. The upper ends of the lifting rods 4040 project upwardly through suitable apertures in the end wall 14 of the casing and are provided at their upper extremities with lifting rings 41 by means of which the lifting rods may be engaged for lifting and lowering the cover of the reaction pot. In order to prevent leakage of air into the evacuated casing, each lift-rod aperture in the end wall 14 of the casing is sealed by a sealing gland 42. Moreover, in order to hold the cover in its raised position, one or both of the lift rods may be provided with an adjustable clamp, such as indicated at 43, which may be tightened on one of the lift rods at any predetermined position thereon and by engagement with the corresponding sealing gland of the casing thus serve to hold the cover of the pot in open position.

In carrying out the process of producing titanium metal by the present apparatus, the cover 31 is lowered into engagement with the cover-seat on the upper end of the reaction pot collar to close the latter whereupon magnesium metal billets are introduced into the pot through the feed pipe 36 by way of the air lock 38. Titanium tetrachloride vapors are then fed into the pot by way of the branch pipe 37 of the feed pipe and are reacted with the magnesium metal in the reaction pot. ture in the reaction pot may be controlled by adjusting the temperature of the furnace, indicated generally at 44, in which the assembled casing and reaction pot are mounted. Titanium metal, molten magnesium and magnesium chloride are formed in the reaction pot as reac tion products. During the reaction, the dish-shaped The temperasynapse base-plate constitutes, in efiect, a reservoir which retains the molten magnesium products against leaking out of the joint formed between the upper edge of the base-plate .and the lower end of the pot shell during the initial stages of the reaction. However, after the reaction has proceeded for a suflicient length of time, the titanium sponge formed on the bottom and side walls of the pot automatically seals the joint between the upper edge of the base-plate and thelower end of the reaction pot shell. As the reaction proceeds, the'plug 29in the base-plate may be withdrawn periodically to allow the magnesium chloride being formed to drain out of the pot, the molten magnesium chloride being collected in the lower reduced end of the casing in which it solidifies. In this manner the volume of the magnesium chloride in the pot may be controlled and preferably kept at an optimum minimum value to insure maximum production of titanium metal, maximum efliciency of reaction and most efiicacious sponge density.

Whereas in previous types of apparatus, a high percentage of the volatile reacting materials have been able to escape from the reaction pot during the reaction and to deposit on the adjacent walls of the apparatus and hence cause operational difliculties, the provision of a cover one the reaction pot efiectively prevents the reacting products from escaping thereby etfecting an increased economy in production. In this connection the flowcontrol lip of the reaction pot likewise aids in preventing the reacting materials from spilling over the rim of the reaction pot and being lost against recovery.

The magnesium chloride which does not drain through the aperture in the bottom of the base-plate and the unreacted magnesium metal occluded in the titanium metal sponge may then be removed from the titanium metal sponge by distillation. This is readily effected without exposing the titanium metal to the atmosphere by lifting the cover 31 upwardly away from the open upper end of the reaction pot whereupon the subatmospheric pressure in the casing causes the unreacted magnesium metal and the residual magnesium chloride to vaporize and rise upwardly from the titanium sponge and to condense on the walls of the head-portion of the casing and/or be carried ofi by way of the evacuating-means thereof. The titanium metal in the reaction pot is thus left in a substantially purified state. Upon completion of the distilling and operation and cooling of the reaction pot, the latter is removed from the casing, whereupon its separable collar 20a and base-plate 25 are removed leaving a substantially straight cylindrical shell from which the metal sponge may be readily removed.

By the apparatus of this invention, the production of substantially pure titanium metal sponge by reaction of titanium tetrachloride with magnesium metal may be carried out under controlled conditions, in the absence of contact with the atmosphere and with substantially no leakage of the reacting products from the reaction pot.

The improved apparatus of this invention thus provides for the production of substantially pure titanium metal efliciently and economically and actual test runs on the the apparatus have shown an efiiciency as high as 97% based on the recovery of titanium.

While this invention has been described and illustrated by the illustration shown herein, its is not intended to be strictly limited thereto and other modifications and variations may be employed within the scope of the following claims.

We claim:

1. In an apparatus for producing titanium metal by reacting titanium tetrachloride with a reducing metal, the combination including: a substantially air-tight unitary enclosure having a head portion at its upper end defining a condensing zone; evacuating means connected to said head portion to evacuate the condensing zone; a base portion at the lower end of said enclosure; a reaction pot supported in said enclosure between said head portion and said base portioma cover for said reaction pot, said cover having a central aperture extending therethrough; a reactant feed pipe fixedly supported in said head portion and arranged to extend through the aperture of said cover both to feed the reactants into said reaction pot and to constitute guide means for movement of said cover vertically relative to said pot; pot cover operating means arranged externally of said air-tight enclosure to move said pot cover relative to said pot; and means to heat the reactants in said reaction pot to form volatile reactants and titanium metal therein, said evacuating means being arranged to evacuate said condensing zone when said pot cover is raised relative to said reaction pot, thereby to efliect the separatiofi and removal of the volatile reactants in said pot from the titanium metal.

2. In an apparatus for producing titanium metal by reacting titanium tetrachloride with a reducing metal, the combination including: a substantially air-tight unitary enclosure having a head portion at its upper end defining a condensing zone; evacuating means connected to said head portion to evacuate the condensing zone; a base portion at the lower end of said enclosure; a reaction pot supported in said enclosure between said head portion and said base portion; a collar on the upper end of said reaction pot, said collar having an inwardly extending lip; a cover for said reaction pot, said cover having a central aperture extending therethrough and a downwardly projecting protuberance arranged to seat on the inwardly projecting lip of said reaction pot collar; a reactant feed pipe secured in the head portion of said enclosure, said feed pipe being arranged to extend through the aperture of said cover both to feed the reactants into said reaction pot and to constitute guide means for movement of said cover vertically relative to said pot; pot cover operating means arranged externally of said air-tight enclosure to move the protuberance of said pot cover to and from engagement with the lip of said collar; and means to heat the reactants in said reaction pot to form volatile reactants and titanium metal therein, said evacuating means being arranged to evacuate said condensing zone when said pot cover is raised oil of said pot collar, thereby to effect the separation and removal of the volatile reactants in said pot from the titanium metal.

3. In an apparatus for producing titanium metal by reacting titanium tetrachloride with a reducing metal, the combination including: a substantially air-tight unitary enclosure having a head portion at its upper end definmg a condensing zone; evacuating means connected to said head portion to evacuate the condensing zone; a base portion at the lower end of said enclosure; a reaction pot supported in said enclosure between said head portion and said base portion, said reaction pot com prising a substantially cylindrical shell open at its upper and lower ends, a base plate arranged to be removably supported against the bottom open end of said shell, and a collar arranged to be removably supported on the upper open end of said shell, said collar having an inwardly and downwardly inclined lip; a cover for said reactor pot, said cover having a central aperture extending therethrough, and a downwardly projecting protuberance arranged to seat on the inwardly projecting lip of said reaction pot cellar; a reactant feed pipe secured in the head portion of said enclosure, said feed pipe being arranged to extend through the aperture of said cover both to feed the reactants into said reaction pot and to constitute guide means for movement of said cover vertically relative to said pot; pot cover operating means arranged externally of said air-tight enclosure to move the protuberance of said pot cover to and from engagement with the lip of said collar; and means to heat the reactants in said reaction pot to form volatile reactants and titanium metal therein, said evacuating means being arranged to evacuate said condensing zone when said pot cover is raised ofi of the lip of said pot collar to effect the separation and removal of the volatile 'reactants in said pot from the titanium metal.

References Cited in the file of this patent UNITED STATES PATENTS 243,850 Clark July 5, 1881 503,556 Solvay Aug. 15, 1893 1,731,223 Brady Oct. 8, 1929 8 Kroll June 25, 1940 Wolf May 27,- 1941 Morrison Ian. 10, 1950 Maddex June 12, 1951 Maddex Aug. 14, 1951 FOREIGN PATENTS Switzerland July 1, 1942 

1. IN AN APPARATUS FOR PRODUCING TITANIUM METAL BY REACTINGS TITANIUM TETRACHLORIDE WITH A REDUCING METAL, THE COMBINATION INCLUDING: A SUBSTANTIALLY AIR-TIGHT UNITARY ENCLOSURE HAVING A HEAD PORTION AT ITS UPPER END DEFINING A CONDENSING ZONE; EVACUATING MEANS CONNECTED TO SAID HEAD PORTION TO EVACUATE THE CONDENSING ZONE; A BASE PORTION AT THE LOWER END OF SAID ENCLOSURE; A REACTION POT SUPPORTED IN SAID ENCLOSURE BETWEEN SAID HEAD PROTION AND SAID BASE PORTION; A COVER FOR SAID REACTION POT, SAID COVER HAVING A CENTRAL APERTURE EXTENDING THERETHROUGH; A REACTANT FEED PIPE FIXEDLY SUPPORTED IN SAID HEAD PORTION AND ARRANGED TO EXTEND THROUGH THE APERTURE OF SAID COVER BOTH TO FEED THE REACTANTS INTO SAID REACTION POT AND TO CONSTITUTE GUIDE MEANS FOR MOVEMENT OF SAID COVER VERTICALLY RELATIVE TO SAID POT; POT COVER OPERATING MEANS ARRANGED EXTERNALLY OF SAID AIR-TIGHT ENCLOSURE TO MOVE 